Re: [PATCH v1 2/2] rtc: loongson: Add Loongson-2K0300 support

Huacai Chen
2025-12-23T08:40:01Z

Hi, Binbin,

On Tue, Dec 23, 2025 at 2:42 PM Binbin Zhou <zhoubinbin@loongson.cn> wrote:
>
> The Loongson-2K0300's rtc hardware design is similar to that of the
> Loongson-1B, but it does not support the alarm feature.
>
> Introduce `LOONGSON_RTC_ALARM_WORKAROUND`, which indicates a chip that
> does not support the alarm function, and rewritethe related logic in
> `loongson_rtc_alarm_setting()`
>
> Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> ---
> drivers/rtc/rtc-loongson.c | 65 ++++++++++++++++++++++++++------------
> 1 file changed, 44 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
> index 2ca7ffd5d7a9..6b076bd4e24e 100644
> --- a/drivers/rtc/rtc-loongson.c
> +++ b/drivers/rtc/rtc-loongson.c
> @@ -67,6 +67,7 @@
> * Accessing the relevant registers will cause the system to hang.
> */
> #define LS1C_RTC_CTRL_WORKAROUND BIT(0)
> +#define LOONGSON_RTC_ALARM_WORKAROUND BIT(1)
Can we reuse existing logic, which means "alarm_irq =
platform_get_irq(pdev, 0)" return 0 for LS2K0300?

Huacai

>
> struct loongson_rtc_config {
> u32 pm_offset; /* Offset of PM domain, for RTC alarm wakeup */
> @@ -89,7 +90,7 @@ static const struct loongson_rtc_config ls1b_rtc_config = {
>
> static const struct loongson_rtc_config ls1c_rtc_config = {
> .pm_offset = 0,
> - .flags = LS1C_RTC_CTRL_WORKAROUND,
> + .flags = LS1C_RTC_CTRL_WORKAROUND | LOONGSON_RTC_ALARM_WORKAROUND,
> };
>
> static const struct loongson_rtc_config generic_rtc_config = {
> @@ -97,6 +98,11 @@ static const struct loongson_rtc_config generic_rtc_config = {
> .flags = 0,
> };
>
> +static const struct loongson_rtc_config ls2k0300_rtc_config = {
> + .pm_offset = 0x0,
> + .flags = LOONGSON_RTC_ALARM_WORKAROUND,
> +};
> +
> static const struct loongson_rtc_config ls2k1000_rtc_config = {
> .pm_offset = 0x800,
> .flags = 0,
> @@ -299,9 +305,41 @@ static const struct rtc_class_ops loongson_rtc_ops = {
> .alarm_irq_enable = loongson_rtc_alarm_irq_enable,
> };
>
> +static int loongson_rtc_alarm_setting(struct platform_device *pdev, void __iomem *regs)
> +{
> + int ret = 0, alarm_irq;
> + struct device *dev = &pdev->dev;
> + struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
> +
> + if (priv->config->flags & LOONGSON_RTC_ALARM_WORKAROUND) {
> + /* Loongson-1C/Loongson-2K0300 RTC does not support alarm */
> + clear_bit(RTC_FEATURE_ALARM, priv->rtcdev->features);
> + return 0;
> + }
> +
> + /* Get RTC alarm irq */
> + alarm_irq = platform_get_irq(pdev, 0);
> + if (alarm_irq < 0)
> + return alarm_irq;
> +
> + ret = devm_request_irq(dev, alarm_irq, loongson_rtc_isr, 0, "loongson-alarm",
> + priv);
> + if (ret < 0)
> + return ret;
> +
> + priv->pm_base = regs - priv->config->pm_offset;
> + device_init_wakeup(dev, true);
> +
> + if (has_acpi_companion(dev))
> + acpi_install_fixed_event_handler(ACPI_EVENT_RTC,
> + loongson_rtc_handler, priv);
> +
> + return ret;
> +}
> +
> static int loongson_rtc_probe(struct platform_device *pdev)
> {
> - int ret, alarm_irq;
> + int ret;
> void __iomem *regs;
> struct loongson_rtc_priv *priv;
> struct device *dev = &pdev->dev;
> @@ -330,25 +368,9 @@ static int loongson_rtc_probe(struct platform_device *pdev)
> return dev_err_probe(dev, PTR_ERR(priv->rtcdev),
> "devm_rtc_allocate_device failed\n");
>
> - /* Get RTC alarm irq */
> - alarm_irq = platform_get_irq(pdev, 0);
> - if (alarm_irq > 0) {
> - ret = devm_request_irq(dev, alarm_irq, loongson_rtc_isr,
> - 0, "loongson-alarm", priv);
> - if (ret < 0)
> - return dev_err_probe(dev, ret, "Unable to request irq %d\n",
> - alarm_irq);
> -
> - priv->pm_base = regs - priv->config->pm_offset;
> - device_init_wakeup(dev, true);
> -
> - if (has_acpi_companion(dev))
> - acpi_install_fixed_event_handler(ACPI_EVENT_RTC,
> - loongson_rtc_handler, priv);
> - } else {
> - /* Loongson-1C RTC does not support alarm */
> - clear_bit(RTC_FEATURE_ALARM, priv->rtcdev->features);
> - }
> + ret = loongson_rtc_alarm_setting(pdev, regs);
> + if (ret)
> + return ret;
>
> /* Loongson RTC does not support UIE */
> clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, priv->rtcdev->features);
> @@ -379,6 +401,7 @@ static const struct of_device_id loongson_rtc_of_match[] = {
> { .compatible = "loongson,ls1b-rtc", .data = &ls1b_rtc_config },
> { .compatible = "loongson,ls1c-rtc", .data = &ls1c_rtc_config },
> { .compatible = "loongson,ls7a-rtc", .data = &generic_rtc_config },
> + { .compatible = "loongson,ls2k0300-rtc", .data = &ls2k0300_rtc_config },
> { .compatible = "loongson,ls2k1000-rtc", .data = &ls2k1000_rtc_config },
> { /* sentinel */ }
> };
> --
> 2.47.3
>
>